Improvement in processes and furnaces for reducing and smelting ores



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W3. 0. EUSTIS. v Process and Furnace for Reducing and SmeltingOres.

Patented Nov.'5 1878.

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3 Sheets-Sheet 3. W". ;B.]G. EUSTIS. Process and Furnace for Reducingand smelting Ores.

. No. 209,554.- Patenied No'v. 5,1878.

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UNITED TA E-s WILLIAM E. c. EUSTIS, on MILTON, ASSIGNOR or ONE-HALF HISRIGHT TO HENRY M. HOWE,0F BOSTON, MASSACHUSETTS.

IMPROVEMENT lN PROCESSES AND FURNACES FOR REDUClNG AND SMELTlNG ORES.

Specification forming part of Letters Patent No. 209,554, dated November5, 1878; application filed September 8, 1877.

Mechanism and Process for Reducing and- Smelting Ores, of which thefollowin gis a specification:

This invention relates to mechanism by which to reduce and smelt ores ofcopper, iron, &c., and also to a method or process of reducing orsmelting such ores, as hereinafter set forth.

I will first describe the invention as applied to the reduction orsmelting of copper, which is generally combined with iron-ore.

To separate the copper, I employ amixture composed chiefly ofhighly-heated carbonic oxide or other reducing gases and highlyheatedcarbonic-acid gas or steam, this mix ture reducing the copper, but notthe iron, to the metallic state.

I employ, for the reduction of that portion of the ore which it isdesired to reduce, such a combination of gases as will act upon andreduce to the metallic state the desired ore and be inert upon otherspresent in the furnace.

In this invention the gas-producer is fed with the products ofcombustion of the combustion-chamber rather than with air, whereby amaterial portion of the actual energy of the heat of the flame of thecombustion-chamber is converted into potential energy, thus making theproducer a recuperator, capable of giving the same result as theregenerator of other furnaces.-

To enable the producer to act as a recuperator, Ipass a portion of theproducts of combustion of the combustion-chamber directly into the fuelin the producer, thereby reducing the carbonic acid of the products ofcombustion into carbonic oxide, whereby with a given amount of fuel inthe producer I am enabled to supply at the combustion-chamber double theamount of combustible gas that would be possible with a producer havinga like amount of fuel and fed with air rather than with products ofcombustion.

It will thus be seen that the actual energy that existed in the productsof combustion in the combustion-chamber in the condition of heat nowbecomes potential energy contained in the combustible gas, to be carriedforward and converted again into actual energy in the combustion-chamberby burning the gas.

This last-mentioned chemical operation, although producing double theamount of gas with a like expenditure of fuel, causes a very vgreatlowering of temperature in the gas-producer, equivalent to about 1,000centigrade. This large amount of gas led from the gas-producers to thecombustion-chamber is there' mixed with heated air which has not beenpassed through fuel, and is effectually consumed, producing intenseheat.

In some forms of furnaces the air to feed the producer is heated by theoutgoing products of combustion, causing an enormously high temperaturein the producer, while in our case theproducts of combustion fed to theproducer cause alowering of the temperature;

and by as much as the heat generated in our producer is less than thatgenerated in the hot-air form, by so much is the heat produced in ourcombustion-chamber greater than that produced in the combustion-chamberof such hot-air form.

The products of combustion are herein carried from thecombustion-chamber to the producer by means of a steam-jet from apipe,33, connected with a suitable steam-supply. This jet is capable, also,by means of suitable apparatus of drawing along with the products ofcombustion alarge amount of air,by means of which the temperature of theproducer can at any time be raised to any desired point, so that bymeans of the steam on the one hand and air on the other the temperatureof the producer is absolutely under control. This lowering oftemperature is of great advantage, in that it saves wear of thebrick-work.

Figure 1 represents, in top view, suflicient of a reducing and smeltingfurnace to illustrate this invention 5 Fig. 2, a vertical longitudinalsect-ion taken on the lines E F, G H, J K, L M, Fig. 1; Fig. 3, avertical cross-section on line A B, Fig. 1; and Fig. 4, a cross sectionon line C D. a

The ore to be reduced is placed in the shaft 2, it being introducedthrough suitable openings 3 at the top. The fuel to produce the gas isplaced in the chambers 4 4 of the producer, four such producers beingshown. Each chamber is provided with arches or projecting portions 5 6,to so hold the fuel as to form air-spaces 7 8 9 10. The air to supportcombustion is introduced into the combustionchamber through any usual orsuitable airheating apparatus, 40, called a fecuperator. (Not necessaryto be herein described.) The fire having been kindled in theproducer-chambers to be used, the operation is as follows: Thecombustible reducing-gas passes through the checker-work of the producerinto a space, 12, between the checker-work and door 13, or it may be thewall, and thence into a flue, 14, Fig. 2, from which lead two downwardflues, 15, (one only being shown,) into the combustion-chamber 11, asdesignated by full arrows. The heated air from the recuperator entersthe combustion-chamber 11 through the hotair flue 16, where it meets thegases from the producer, such gases moving along flue 15. The gas andair so united in the combustionchamber ignite and pass around suchchamber, a part passing out through a flue, 17, like the flue 16, it,however, leading to the recuperator, and a part through the producerflue18, thence through ports 19 (shown only at the left of Fig. 2) to theproducer-chambers 4, each of which chambers have ports, like 19,connecting it with the flue 18. The products of combustion thus led fromthe combustionchamber to the producers, for the purposes previouslydescribed in this specification, issue from the ports 19 and enter thefuel through its natural slope, as shown, next the space 8,

instead of through grate-bars thence through the column of fuel, asindicated, between spaces 7, 8, and 9 issuing thence, through the spaces7 and 9, and the checker-work 20, into space 12 and flues 14 15, asbefore described, the

products of combustion, by their passage through the glowing fuel, beingconverted into combustible gases containing potential energy and loweredin temperature, as before described. 7

In this invention the fuel is sustained by the arches or projections insuch manner that the products of combustion from ports 19 have freepassage therethrough, as if supported on grate-bars, which, if hereinused, could not stand the degree of heat employed.

Another important feature of this invention is, that the products ofcombustion used to feed the producers are made to pass directly throughthe hottest part only of the mass of fuel, instead of through the cooltop crust of the fuel, as in common practice. I gain by this that anymoisture contained in the fuel (there always being more or less) isresolved into its constituent gases-hydrogen and oxygen. The hydrogen soproduced forms, with i the fuel, hydrocarbons. The oxygen forms carbonicoxide, and these two combustible gases are carried forward to thecombustionchamber, whereas in common practice steam only would becarried forward. For the same reason, hydrocarbon gases being highlyheated become more stable, and will not, therefore,

deposit in the flues. A portion of the carbonic oxide passes from theflue 14 into shaftflue 21. (Shownin dotted lines, Figs. 1 and 2.) Aflue, 23, leads from the highly-heated combustion-chamber into the flue21, and conducts the non-reducing carbonic-acid gas of thecombustion-chamber at high temperature into and mixes it with thereducing carbonic oxide and hydrocarbons in flue 21, they also, at hightemperature, passing directly from the gas-producers to the stack, andsuch combined gases entering the mass of ore in the shaft 2 act, asbefore described, to reduce to the metallic state the desired part ofthe ore and re main inert upon others present in the furnace, theproportion of these gases being regulated by means of suitable dampersin the flues 21 and 23. a

The most reduced ore is always at the bottom of the shaft on theshaft-hearth, where it is protected from the oxidizing-atmosphere of thecombustion-chamber by a seal of usual construction, as at 24, mademovable in suitable guideways. At the bottom of this shaft it melts andruns over the bank 25, into the hearth of the combustion-chamber, or ispushed over by an operator by means of a rabble inserted through thedoor 26. This hearth is made double by means of the bank 25, in order toallow of continuous working of the shaft 2, for it is at times desirableto treat the metal on the hearth of the combustionchamber separate fromthaton thehearth of the shaft. The metal is finally drawn from thehearth of the combustion-chamber through the tap-hole 27.

By means of suitable dampers in passages 30 either of the gas-producingchambers may be cut off from the others to clean them,and when either ofthe producer-chambers crossed by the line A B, Fig. 1, is so cut off thepipe 29 connects the two chambers at, the end of the furnace.

In Figs. 2 and 3, 28 represents a rest to support false grate-bars whenit is desired to clean the fire, as, for instance, by removing the wastebelow the arch 6.

So far this invention has been described for operation upon copper orescontaining more or less iron; but it is obvious that it is applicable tothe reduction of other compound ores, 1t being only necessary to supplysuch ores with the proper combination of reducing-gases.

Portions of this invention are applicable to melting as well as smeltingfurnaces. All the producers are provided with checker-work and flues, asdescribed. The shaft with its hearth constitute a shaft-furnace, and thecombustion-chamber is simply that of areverberator furnace.

The producers are placed very closeto the combustion-chamber to avoidthe loss of heat which would result in conducting the gases throughpipes, as in some other forms of fur naces.

For treating a compound ore of copper and iron, Ihave found. 50 O0 to 5000 at a brightred heat to reduce copper entirely to the metallic state,and not to give a trace of metallic iron.

If the ore is a sulphuret it should be calcined before being placed in.the stack.

I claim- 1. The herein-described process of reducing one metal of acompound ore while the other metals therein remain unreduced, whichconsists in subjecting the ore in a furnace or shaft to a mixture ofreducing and non-reducing gases in proportions and under conditionsappropriate to the particular metal to be red'uced, substantially asherein described.

2. In the working of working ores, the process herein described ofcontinuously generatin g and burning reducing-gases and utilizing theheat therefrom, which consists in passing the products of the combustionof said reducing-gases effected in the combustion-chamber through thefuel in the gas-producer, then conducting the gases so produced to thecombustion-chamber, again admitting thereto a supply of heated air,thereby causing complete combustion, and heating said combustionchamber,and then again conducting the products of this combustion to thegas-producer, thus rendering the process continuous, substantially asdescribed.

3. The combination, with fuel-holding projections 5 6 in the producer,of checker-work 20, substantiallyas described.

4. The shaft to contain the ore to be treated and its hearth, incombination with a reverberatory-furnace and its hearth, placedcontiguous to the shaft-hearth, but separated therefrom by a bridge, andwith the gate 24, to protect the reduced ore in the shaft and its hearthfrom the action of the oxidizing-gases in the combustion-chamber,substantially as setforth.

5. The hearth of the combustion-chamber and a flue, 15, to receive thegases from the producers, in combination with a fine, 16 or 17, to carrya part of the products of combustion to a recuperator, and a secondflue, 18, to carry another portion of such products of coinbustion backto the producers, to operate substantially as described.

In testimony whereof I have signed my name to this. specification in thepresence of two subscribing witnesses.

WILLIAM E. (J. EUSTIS.

Witnesses:

G. W. GREGORY, W. J. PRATT.

